Dean Saunders is reportedly the leading candidate to succeed Paul Cook as Chesterfield manager.
The Spireites are looking for a new boss after Cook left to join Portsmouth on Tuesday, and according to Sky Sports News Saunders is their main candidate.
Cook spent nearly three seasons at the Proact Stadium and departed after guiding the Derbyshire side to the League One playoffs this term.
The 50-year-old could not prevent the Red Devils from suffering relegation to League Two and it is thought that he is discussing his long-term future with the club, with Gregory unlikely to return.
Saunders has also previously managed Wrexham and Doncaster Rovers.